Add follow_symlink argument to Inotify observer

[Corentin-pro]

Adding follow_symlink as keyword argument allow to have recursive watch consistent with the polling method.

This makes the change from PR #109 the default behavior but not the only option. The default values being False this changes will not change nor break any previous use of the library.

Fixes #365.

Ruff is OK and 2 tests are not passing (were not passing before changes either on my computer):

• test_0_watchmedo.py::test_kill_auto_restart : threading.active_count() == old_thread_count -> assert 1 == 2
• test_inotify_c.py::test_select_fd: stack.enter_context(open(path)) -> OSError: [Errno 24] Too many open files: '/tmp/[...]/pytest-1/test_select_fd0/new_file', my ulimit is unlimited

[Corentin-pro]

@BoboTiG I ran tox (fixed some code format) and find the mypy issue, the added follow_symlink keyword is now in the schedule function of FSEventObserver too.

I don't know what should I add in the changelog, I couldn't find examples in previous PR.